This PR separates the unloading phase into two stages - slow unload from the fsensor and "fast" unload to FINDA. The MMU behaved like this since the beginning, the two stages were just hidden under one progress state and the printer had no chance of checking whethere the MMU already pulled those 40mm from the fsensor or not.
The intent is to allow tighter cooperation with the printer - after the printer thinks it unloaded the filament from the drive gear, we'll still rotate the drive gear as long as the MMU reports progress state UnloadingFromFSensor. This approach should solve the issue with long strings holding the filament in place while the MMU is trying to pull it out of the extruder. Not much of a problem on MK3 where the Bondtech gears cannot clamp thin strings, but a serious problem on the MK4 where the drive gear can hold even thin long strings.
After those 40mm of slow unload distance, the MMU checks the fsensor (like is has been doing before).
If FSensor is off at this moment, everything is fine a the unload will continue at full speed.
This PR separates the unloading phase into two stages - slow unload from the fsensor and "fast" unload to FINDA. The MMU behaved like this since the beginning, the two stages were just hidden under one progress state and the printer had no chance of checking whethere the MMU already pulled those 40mm from the fsensor or not.
The intent is to allow tighter cooperation with the printer - after the printer thinks it unloaded the filament from the drive gear, we'll still rotate the drive gear as long as the MMU reports progress state UnloadingFromFSensor. This approach should solve the issue with long strings holding the filament in place while the MMU is trying to pull it out of the extruder. Not much of a problem on MK3 where the Bondtech gears cannot clamp thin strings, but a serious problem on the MK4 where the drive gear can hold even thin long strings.
After those 40mm of slow unload distance, the MMU checks the fsensor (like is has been doing before). If FSensor is off at this moment, everything is fine a the unload will continue at full speed.
MMU-225